This invention relates to turntable rotation control devices, and more particularly to a turntable rotation control device in a record player with an automatic playback device.
In general, in a record player, the turntable on which a record is placed is rotated after the tone arm is horizontally swung towards the inner circumference of the record from the arm rest position. In this connection, no trouble is encountered if the record player is manually operated. However, difficulties in operation occur in the situation of a record player with an automatic playback device. In this type of record player, first, the tone arm is elevated by the elevation mechanism in response to the automatic playback start instruction. When the tone arm is elevated, it is not swung horizontally, and therefore the rotation of the turntable will not start. Accordingly, in some cases the user may have the impression that the player is out of order since operation is not initiated.
In some record players with automatic playback devices, the turntable is rotated during the operation of the playback device. These record players accordingly do not suffer from the above-described difficulty. However, in the record player of this type, the turntable is continuously rotated until the tone arm is lowered on the arm rest even if the tone arm has been returned to that arm rest position. This may be also mistaken for a failure of the player. Additionally, power consumption is increased since the motor is needlessly rotated. This is an additional difficulty accompanying the conventional player with an automatic playback device.
Accordingly, an object of this invention is to eliminate all of the above-described difficulties accompanying a conventional record player with an automatic playback device.
More specifically, an object of the invention is to provide a turntable rotation control device by which a turntable starts rotation simultaneously, when automatic playback is started, and the rotation of the turntable is stopped when the tone arm returns to the position at an arm rest after the playback is terminated.
These and other objects of this invention are accomplished using a turntable rotation control device having a reversible electric motor. A mechanism is used for horizontally swinging a tone arm towards the inner circumference of a record by the rotation of the motor in a first direction. A second mechanism is employed for horizontally swinging the tone arm towards the outer circumference of the record by rotation of the motor in a second direction.
First and second signal generating devices are employed to reversibly drive the motor. A detecting circuit senses when the tone arm has been swung horizontally from an initial position at an arm rest and an OR gate circuit generates an output comprising the logical sum of output signals of the first signal detecting circuit and the detecting circuit. A drive circuit, controlled by OR gate output is used to control rotation of the turntable.
These aspects of the invention will become apparent from the drawings and the description of the preferred embodiment which follow.